1. Field of the Invention
The present invention relates to a case type power semiconductor apparatus which encloses a power semiconductor element and a control semiconductor element with a case, and more particularly, to a power semiconductor apparatus providing excellent productivity and moreover excellent recyclability which facilitates reuse of the case.
2. Background Art
In recent years, there is a growing demand for IPM modularization of an IGBT module (Insulated Gate Bipolar Transistor) used for industrial motor control and servo applications. Here, “IPM” is a power module which incorporates a drive circuit and a self protection function for a power device such as a MOSFET and IGBT which controls power.
A mold type IPM is used for consumer applications. This mold type IPM is made up of an IC and a power semiconductor chip (IGBT, diode) which are die-mounted on a Cu frame and consolidated with epoxy mold resin. There is also a proposal of a mold type IPM provided with a heat sink to improve a heat radiation characteristic (for example, see Japanese Patent Laid-Open No. 2001-085613).
On the other hand, a case type IPM is used as a small/medium capacity industrial IPM (600V/50 A or above). FIG. 3 is a sectional view showing a conventional case type IPM and FIG. 4 is a top view thereof. An insertion case 1 incorporates an insulating substrate 4 mounted with an IGBT chip 2 and a diode 3 as power semiconductor elements and a mounting substrate 5 mounted with a control IC as a control semiconductor element, resistors and capacitors. These components are connected to each other using Al wires 6.
Furthermore, the IGBT chip 2 and diode 3 are connected to the outside through a power terminal 7 incorporated in the insertion case 1. The mounting substrate 5 is connected to the outside through a control terminal 8 incorporated in the insertion case 1. Furthermore, a Cu base 9 is formed on the back side of the insulating substrate 4 to radiate heat from the IGBT chip 2 and diode 3. Moreover, case rings 10 are provided in the four corners of the insertion case 1.
However, compared to the mold type IPM, the case type IPM includes more parts and requires higher assembly cost, and is therefore inferior in productivity. Furthermore, as in the case of the mold type IPM, the case type IPM involves a problem that when the case is filled with resin, the case cannot be reused.